This invention relates to a current sensor intended for use in an electrical apparatus such as a residual current detection device, a current meter or a power meter.
It is an object of the present invention to provide a current sensor in an economical form.
In accordance with the invention there is provided a current sensor comprising a metallic link member having two end portions of conductive material and an intermediate portion interconnecting the end portions, said intermediate portion being formed of a resistive material, and an integrated circuit analog to digital converter mounted on said link member, said converter having analog input terminals connected to respective ones of said two end portions and digital output terminals for connection to a processing apparatus.
Conveniently, the converter is attached to the intermediate portion by a layer of electrically insulative adhesive material and the analog input terminals of the converter are connected to the end portions by wire bonds.
The converter preferably includes a delta-sigma modulator which provides a high frequency one-bit digital data. One or more decimation filtering stages may be included in the converter.
The converter may also have a voltage reference terminal for connection to a reference voltage source, the converter operating to provide digital output signals respectively representing the current flowing through said intermediate portion and digital output signals representing the voltage on one of said end portions.